SAIP2015

Density functional theory calculation of surface properties of pyrite (100) and depression of pyrite using TGA.

30 Jun 2015, 16:10

1h 50m

Board: A.374

Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster1

Speaker

Mr Masilu Godfrey Mulaudzi (University of Limpopo)

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD, N/A)?

PhD

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

no

Please indicate whether<br>this abstract may be<br>published online<br>(Yes / No)

no

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

yes

Main supervisor (name and email)<br>and his / her institution

P.E Ngoepe(phuthi.ngoepe@ul.ac.za)/University of Limpopo

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

The structural relaxation, atomic Mulliken populations and electronic structures of ideal pyrite (100) surface were calculated using density functional theory (DFT). The calculated results show that the relaxation of pyrite (100) surface is relatively small, and the Fe-S interaction increases at the surface compared to that in the bulk. The calculated electronic structure results suggest that the surface 5-coordinated Fe atom has high activity. Adsorption of TGA on FeS₂ (100) surfaces is investigated, and results for CaOH⁺ and OH^- adsorption on FeS₂ (100) which are important in the depression process are also reported. The adsorption of thiolglycolic acid, hydroxyl and calcium hydroxyl ions (TGA, OH^- and CaOH^-) on pyrite (100) surfaces was studied using first-principles calculations to investigate the depression of pyrite by TGA, NaOH and CaO. The calculation results showed that the adsorption of CaOH⁺ on pyrite surfaces was stronger than the adsorption of OH^- and TGA. The surface Fe atoms were the active sites for the three adsorbates. The OH obtained electrons from the surface, whereas TGA and CaOH⁺ lost electrons to the surface. The loss of electrons resulted in the accumulation of electrons on the surface, which hindered the oxidation of pyrite and the formation of dixanthogen.